Research Projects
The response of tropical rainfall to past climate changes
We explore how the mean position of the rain belt and the strength of each hemisphere's Hadley circulation have responded to past climate changes, using a combination of data, climate models, and theory. We also work with collaborators to trace the local impact of these global shifts using lake deposits and stalagmites in a variety of regions of the tropics and subtropics, including southeast Asia, Madagascar, northeastern Mexico, and northern Chile. U/Th dates from our group help provide precise chronologies for these records and allow us to map precipitation changes through space and time.
Selected papers:
McGee et al., Earth and Planetary Science Letters 2014
Dust as a tracer of past winds
Windblown mineral dust sensitively responds to changes in winds and aridity, and it also has important impacts on climate and ecosystems. Our group reconstructs the history of windblown dust emissions and transport using deep-sea sediments. Much of our work focuses on North Africa, the world's greatest dust source, but we are also involved in projects tracing dust emitted from East Asia and South America's Atacama Desert.
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Selected papers and news items:
A "pacemaker" for North African climate (MIT News)
Water availability in drylands
Lake deposits and stalagmites in now-dry regions like the southwestern U.S. and northern Chile provide evidence of dramatic hydrological changes in response to past climate changes. Our group profiles these ancient wet periods to understand the drivers of changes in water availability in the sensitive regions, and to provide quantitative tests of climate model performance.
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Selected papers and news items:
Permafrost stability in past warm climates
Permafrost holds twice as much carbon as the atmosphere, but it is unclear how quickly it will release this carbon as it warms. We are using cave deposits from permafrost regions in Canada to document temperatures, atmospheric circulation patterns and permafrost thaw in past warm climates.
Selected papers and news items:
Cave deposits show surprising shift in permafrost (MIT News)
